Ce3+ and Eu2+ coactivated Ca2BO3Cl phosphors exhibit two blue and yellow emission bands under the excitation of UV light. An asymmetric blue emission originates from Ce3+, whereas the yellow emission originates from Eu2+. The luminescent mechanism is explained by the resonance-type energy transfer from Ce3+ to Eu2+, and the energy-transfer efficiency is also calculated by decline and growth of their emission relative intensities. In light of the principle of energy transfer, the varied emitted color of phosphor from blue through white and finally to yellow can be achieved by properly tuning the ratio of Ce3+/Eu2+.